WASHINGTON -- Most women who've had a C-section, and many who've had two, should be allowed to try labor with their next baby, say new guidelines -- a step toward reversing the "once a cesarean, always a cesarean" policies taking root in many hospitals.

Wednesday's announcement by the American College of Obstetricians and Gynecologists eases restrictions on who might avoid a repeat C-section, rewriting an old policy that critics have said is partly to blame for many pregnant women being denied the chance.

Fifteen years ago, nearly 3 in 10 women who'd had a prior C-section gave birth vaginally the next time. Today, fewer than 1 in 10 do.

Last spring, a National Institutes of Health panel strongly urged steps to reverse that trend, saying a third of hospitals and half of doctors ban women from attempting what's called VBAC, for "vaginal birth after cesarean."

The new guidelines declare VBAC a safe and appropriate option for most women -- now including those carrying twins or who've had two C-sections -- and urge that they be given an unbiased look at the pros and cons so they can decide whether to try.

Women's choice is "what we want to come through loud and clear," said Dr. William Grobman of Northwestern University, co-author of the guidelines. "There are few times where there is an absolute wrong or an absolute right, but there is the importance of shared decision-making."

Overall, nearly a third of U.S. births are by cesarean, an all-time high. Cesareans can be lifesaving but they come with certain risks -- and the more C-sections a woman has, the greater the risk in a next pregnancy of problems, some of them life-threatening, like placenta abnormalities or hemorrhage.

The main debate with VBAC: That the rigors of labor could cause the scar from the earlier surgery to rupture. There's less than a 1 percent chance of that happening, the ACOG guidelines say. Also, with most recently performed C-sections, that scar is located on a lower part of the uterus that's less stressed by contractions.

Of those who attempt VBAC, between 60 percent and 80 percent will deliver vaginally, the guidelines note. The rest will need a C-section after all, because of stalled labor or other factors. Success is more likely in women who go into labor naturally -- although induction doesn't rule out an attempt -- and less likely in women who are obese or are carrying large babies, they say.

Thus the balancing act that women and their doctors weigh: A successful VBAC is safer than a planned repeat C-section, especially for women who want additional children -- but an emergency C-section can be riskier than a planned one.

Because of those rare uterine ruptures, the obstetricians' group has long recommended that only hospitals equipped for immediate emergency C-sections attempt VBACs. Many smaller or rural hospitals can't do that, and that recommendation plus high-dollar lawsuits have been blamed for some hospital VBAC bans.